# Draft California 2012 Integrated Report( 303(d) List/305(b) Report)

# Supporting Information

## Regional Board 6 - Lahontan Region

Water Body Name: | Sheep Creek
Water Body ID: | CAR6282000020070828155444
Water Body Type: | River & Stream

DECISION ID | 21913 | Region 6
Sheep Creek

Pollutant: | Acid Neutralizing Capacity
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Acid Neutralizing Capacity (ANC) is equivalent to alkalinity, and the USEPA "Gold Book" criterion for alkalinity states that it should be greater than 20 mg/L CaCO3 unless natural alkalinity is lower. Only one ANC sample is available for Sheep Creek, and it is below 20 mg/L. There is insufficient information to determine the natural range of ANC. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. It is not possible to determine whether the single sample exceeds the criterion. The minimum sample number requirements of Table 3.2 of the Listing Policy are not met. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21913, Acid Neutralizing Capacity | Region 6
Sheep Creek
LOE ID: | 7961
Pollutant: | Acid Neutralizing Capacity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Sheep Creek under the Region 6 SWAMP program. One sample collected on March 20, 2003 was analyzed for ANC. The result was 7.8 mg/L CaCO3.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There are no California or federal standards or criteria for acid neutralizing capacity (ANC) per se. However, ANC is equivalent to alkalinity, and the U.S. Environmental Protection Agency "Gold Book" recommends alkalinity greater than 20 mg/L CaCO3 unless natural alkalinity is lower.
Objective/Criterion Reference: | Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | One sample was collected on March 20, 2003.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 22029 | Region 6
Sheep Creek

Pollutant: | Boron
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable criterion and water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 9 samples exceeded the California State Notification Level criterion. None of 5 annual average datapoints exceeded the site-specific water quality objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 22029, Boron | Region 6
Sheep Creek
LOE ID: | 5292
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled boron under the Region 6 SWAMP program between 2001 and 2005. Boron concentrations in 7 of 9 samples were estimated or below detection level values. Concentrations in the remaining samples were 9.9 and 24 ug/L. The annual average objective was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective from Lahontan Basin Plan Table 3-21 includes an annual average boron concentration of 0.01 mg/L (or 10 ug/L), and a 90th percentile value of 0.02 mg/L (or 20 ug/L).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Nine samples were collected between 2001 and 2005. One sample was collected in 2001, and samples were collected quarterly between December 2002 and July 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 22029, Boron | Region 6
Sheep Creek
LOE ID: | 7960
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 9
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled boron under the Region 6 SWAMP program between 2001 and 2005. Boron concentrations in 7 of 9 samples were estimated or below detection level values. Concentrations in the remaining samples were 9.9 and 24 ug/L. The criterion was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The California State Notification Level criterion is 1000 ug/L.
Objective/Criterion Reference: | Compilation of Water Quality Goals
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Nine samples were collected between 2001 and 2005. One sample was collected in 2001, and samples were collected quarterly between December 2002 and July 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 22038 | Region 6
Sheep Creek

Pollutant: | Chloride
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level. Four of five annual average datapoints (based on 2-4 samples per year) exceed the site-specific objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 12 samples exceeded the Maximum Contaminant Level. Four of five annual average datapoints exceeded the site-specific objective, and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 22038, Chloride | Region 6
Sheep Creek
LOE ID: | 5296
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 4
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled chloride under the Region 6 SWAMP program between 2001 and 2005. Chloride concentrations in 12 quarterly samples ranged from 5.08 to 27.2 mg/L. The annual average objective was violated in 4 of 5 years.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site specific objective from Lahontan Basin Plan Table 3-21 includes an annual average chloride concentration of 6.0 mg/L and a 90th percentile value of 7.8 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 22038, Chloride | Region 6
Sheep Creek
LOE ID: | 5297
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled chloride under the Region 6 SWAMP program. Chloride concentrations in 12 quarterly samples ranged from 5.08 to 27.2 mg/L. The MCL was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for chloride is 250 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21252 | Region 6
Sheep Creek

Pollutant: | Dissolved oxygen saturation
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the diel, seasonal and annual variability expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region. 3. None of 3 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21252, Dissolved oxygen saturation | Region 6
Sheep Creek
LOE ID: | 5820
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled percent saturation of dissolved oxygen under the Region 6 SWAMP program in 2004 and 2005. Percent saturation in three samples ranged from 93 to 100 percent. The objective was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The water quality objective in the Lahontan Basin Plan states that percent saturation shall not be depressed by more than 10 percent and the minimum dissolved oxygen concentration shall not be less than 80 percent saturation.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Three samples were collected quarterly between November 2004 and July 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21070 | Region 6
Sheep Creek

Pollutant: | Fluoride
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of nine individual samples exceeded the Maximum Contaminant Level. None of five annual average data points exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21070, Fluoride | Region 6
Sheep Creek
LOE ID: | 5298
Pollutant: | Fluoride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled fluoride under the Region 6 SWAMP program between 2001 and 2005. Fluoride concentrations in 9 quarterly samples were all estimated or below detection level values. The annual average objective was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site specific objective from Lahontan Basin Plan Table 3-21 includes an annual average fluoride concentration of 0.13 mg/L and a 90th percentile value of 0.22 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Nine quarterly samples were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21070, Fluoride | Region 6
Sheep Creek
LOE ID: | 5299
Pollutant: | Fluoride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 9
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled fluoride under the Region 6 SWAMP program between 2001 and 2005. Fluoride concentrations in 9 quarterly samples were all estimated or below detection level values. The MCL was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for fluoride is 2 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Nine quarterly samples were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 22039 | Region 6
Sheep Creek

Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 12 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: |

Line of Evidence (LOE) for Decision ID 22039, Nitrate/Nitrite (Nitrite + Nitrate as N) | Region 6
Sheep Creek
LOE ID: | 7964
Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled nitrite plus nitrate under the Region 6 SWAMP program between 2001 and 2005. Of 12 quarterly samples, one was below the detection level and two were estimated values. Nitrite plus nitrate concentrations in the remaining samples ranged from 0.046 to 0.213 mg/L. The MCL was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite plus nitrate (expressed "as nitrogen") is 10 is mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21905 | Region 6
Sheep Creek

Pollutant: | Nitrite
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 12 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21905, Nitrite | Region 6
Sheep Creek
LOE ID: | 7963
Pollutant: | Nitrite
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled nitrite under the Region 6 SWAMP program between 2001 and 2005. Of 23 quarterly samples, 6 had nitrite concentrations below the detection level and one was an estimated value. Nitrite concentrations in the remaining samples ranged from 0.001 to 0.007 mg/L. The MCL was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite is mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21219 | Region 6
Sheep Creek

Pollutant: | Oxygen, Dissolved
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. One of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. One of ten samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21219, Oxygen, Dissolved | Region 6
Sheep Creek
LOE ID: | 5305
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 10
Number of Exceedances: | 1
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey samplex dissolved oxygen under the Region 6 SWAMP program between 2001 and 2005. Dissolved oxygen concentrations in 10 samples ranged from 3.7 to 10.1 mg/L. One sample was below the 1-day minimum objective.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable water quality objective from Lahontan Basin Plan Table 3-6 is a 1-day minimum concentration is 4.0 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station, Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead, was sampled.
Temporal Representation: | Ten samples were collected approximately quarterly between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21902 | Region 6
Sheep Creek

Pollutant: | Phosphate
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. One of the annual average datapoints exceeds the site-specific water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. One of five annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21902, Phosphate | Region 6
Sheep Creek
LOE ID: | 7985
Pollutant: | Phosphate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 1
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Sheep Creek under the Region 6 SWAMP program between 2001 and 2005. Concentrations of PO4 in 12 samples included two estimated values and two values below the detection level. Concentrations in the remaining samples ranged from 0.012 to 0.057 mg/L. In two of five years, samples were all estimates or below the detection level. Calculated annual average PO4 concentrations in the remaining samples were 0.014, 0.097 and 0.016 mg/L. The annual average objective was exceeded in one of 5 years. Two additional samples were collected for dissolved hydrolyzable P plus PO4; one of these samples was 0.02 mg/L and the other was below the detection level.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective for Deep Creek Station 5, from Lahontan Basin Plan Table 3-21, applies under the tributary rule. The objective includes an annual average total dissolved orthophosphate concentration of 0.05 mg/L, and a 90th percentile value of 0.13 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples (2 to 4 per year) were collected for PO4 between 2001 and 2005 Two additional samples for dissolved hydrolyzable P plus PO4 in October 2001 and February 2002.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 28253 | Region 6
Sheep Creek

Pollutant: | Phosphorus
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence are available in the administrative record to assess this pollutant. No biological data are available for assessment whether any of the chemical samples exceeds the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy due to an error in the SWAMP QAPP regarding holding times for total phosphorus samples. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. No biological data are available for assessment of compliance with the water quality objective and the data cannot be assessed using Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 28253, Phosphorus | Region 6
Sheep Creek
LOE ID: | 8046
Pollutant: | Phosphorus
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Sheep Creek under the Region 6 SWAMP program between 2002 and 2005. One of 8 quarterly samples for total phosphorus was an estimated value and two samples were below the detection level. Concentrations of total phosphorus in the remaining samples ranged from 0.033 to 0.072 mg/L. No biological data are available for assessment of compliance with the objective for biostimulatory substances.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There is no site-specific numeric objective for total phosphorus for Sheep Creek. The Lahontan Basin Plan's narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Eight quarterly samples (1 to 4 per year) were collected between 2002 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Sampling and analysis were done according to the SWAMP QAPP. However, in July 2009 an error was discovered in the QAPP related to holding times for total phosphorus samples that affects the validity of data for the Lahontan Region The holding time for samples that are not acid-preserved.should be 48 hours rather than 28 days as indicated in the QAPP. "Low level" phosphorus analyses, without acid preservation, are used in the Lahontan Region's SWAMP program. .
QAPP Information Reference(s):

DECISION ID | 20740 | Region 6
Sheep Creek

Pollutant: | Specific Conductance
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and dissolved ion concentrations in streams of the Lahontan Region. 3. None of fourteen samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: |

Line of Evidence (LOE) for Decision ID 20740, Specific Conductance | Region 6
Sheep Creek
LOE ID: | 5300
Pollutant: | Specific Conductance
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured specific conductance under the Region 6 SWAMP program. Eleven laboratory measurements of specific conductance ranged from 118 to 249 uS/cm. Three field measurements ranged from 183 to 305 uS/cm. The objective was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for specific conductance is 900 microsiemens per centimeter (uS/cm).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Eleven laboratory measurements and three field measurements were taken approximately quarterly between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21220 | Region 6
Sheep Creek

Pollutant: | Sulfates
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the Maximum Contaminant Level. Two of five annual average datapoints exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 12 individual samples exceeded the MCL and this does not exceed the allowable frequency in Table 3.2 of the Listing Policy. Two of five annual average datapoints exceeded the site-specific water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21220, Sulfates | Region 6
Sheep Creek
LOE ID: | 5301
Pollutant: | Sulfates
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled sulfate under the Region 6 SWAMP program between 2001 and 2005. Sulfate concentrations in 12 quarterly samples ranged from 1.3 to 9.5 mg/L. The MCL was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for sulfate is 250 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21220, Sulfates | Region 6
Sheep Creek
LOE ID: | 5302
Pollutant: | Sulfates
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 2
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled sulfate under the Region 6 SWAMP program. Sulfate concentrations in 12 samples ranged from 1.3 to 9.5 mg/L. The annual average objective was violated in two of five years.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective from Lahontan Basin Plan Table 3-21 includes an annual average sulfate concentration of 3.4 mg/L, and a 90th percentile value of 6.9 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20854 | Region 6
Sheep Creek

Pollutant: | Temperature, water
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative temperature objective is an antidegradation-based objective that requires that there be no change in temperature in waters designated for the Cold Freshwater Habitat (COLD) beneficial use. The objective does not include specific numerical limits for protection of the COLD use. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. There are not enough temperature samples to establish baseline conditions (including diel, seasonal, annual and interannual variations in temperature) or to detect declining trends in the temperature regime if such trends exist. Because temperature samples were collected only quarterly, weekly and monthly average data are not available for comparison with guidelines in the scientific literature for the temperature requirements of sensitive aquatic species such as salmonids, as directed in Listing Policy Section 6.1.5.9.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20854, Temperature, water | Region 6
Sheep Creek
LOE ID: | 5307
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured water temperature under the Region 6 SWAMP program between 2001 and 2005. Temperatures in 12 measurements ranged from 3.5 to 17 degrees Celsius. Sampling frequency was insufficient to allow determination of the natural temperature regime or to detect changes.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The relevant language from the Lahontan Basin Plan's temperature objective is as follows: "The natural receiving water temperature of a l waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses. For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve temperature measurements were taken between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 28254 | Region 6
Sheep Creek

Pollutant: | Total Kjeldahl Nitrogen (TKN)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological data are available to assess whether any of the chemical samples exceeds the water quality objective for biostimultory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. No biological data are available for assessment of compliance with the water quality objective and the data cannot be assessed using Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 28254, Total Kjeldahl Nitrogen (TKN) | Region 6
Sheep Creek
LOE ID: | 8047
Pollutant: | Total Kjeldahl Nitrogen (TKN)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Sheep Creek under the Region 6 SWAMP program between 2001 and 2005. One of 12 quarterly sampling results for TKN was below the detection level and 4 samples were estimated values. Concentrations of TKN in the remaining samples ranged from 0.06 to 0.46 mg/L. No biological data are available for assessment of compliance with the objective for biostimulatory substances.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There is no site-specific numeric objective for Total Kjeldahl Nitrogen (TKN) for Sheep Creek. The Lahontan Basin Plan's narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 28436 | Region 6
Sheep Creek

Pollutant: | Total Nitrogen as N
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. One of five annual average datapoints exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. One of 5 annual average datapoints exceeded the site-specific water quality objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 28436, Total Nitrogen as N | Region 6
Sheep Creek
LOE ID: | 8063
Pollutant: | Total Nitrogen as N
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 1
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Sheep Creek under the Region 6 SWAMP program between 2001 and 2005. Twelve quarterly samples each were collected for total Kjeldahl nitrogen and nitrite plus nitrate. Total nitrogen was calculated from these samples. Due to estimated and below detection level values in the component samples, 6 of 12 total nitrogen values were estimates. The remainder of the calculated total nitrogen concentrations ranged from 0.196 to 0.528 mg/L. Three of five annual averages (calculated from 2 to 3 total nitrogen values) were estimates. One of five annual averages was in violation of the objective.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective for Deep Creek Station 5, from Lahontan Basin Plan Table 3-21, applies under the tributary rule. The objective includes an annual average total nitrogen concentration of 0.3 mg/L, and a 90th percentile value of 0.7 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples each (2 to 4 per year) were collected for total Kjeldahl nitrogen and nitrite plus nitrate.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20842 | Region 6
Sheep Creek

Pollutant: | pH
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative pH objective is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units in waters designated for the Cold Freshwater Habitat (COLD) or Warm Freshwater Habitat beneficial uses. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. The data meet data quality requirements of the Listing Policy. However, there are not enough pH samples to establish baseline conditions (including diel, seasonal, annual and interannual variations) or to detect changes in the pH regime due to controllable factors, if such trends exist.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20842, pH | Region 6
Sheep Creek
LOE ID: | 5306
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled pH under the Region 6 SWAMP program between 2001 and 2005. Eleven pH measurements ranged from 7 to 7.5 units. There were too few samples to define the normal pH regime or to allow detection of change.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's objective for pH states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Eleven field pH measurements were taken approximately quarterly between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 28377 | Region 6
Sheep Creek

Pollutant: | Nitrate
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Sources: | Source Unknown
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous listing cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged and is as follows: Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). Three annual average datapoints exceed the water quality objective. However, listing is not recommended because the data are not temporally representative. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used does not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. None of 12 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. Three out of five annual average datapoints exceeded the site-specific objective and this exceeds the allowable frequency listed in Table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. State Board Review and Conclusion: The April 19, 2010 State Water Board staff report for the 2010 Integrated Report recommended to place this water body on the 303(d) list for nitrate based on the State Water Board staff determination that the data were collected over a broad period of time to meet section 6.1.5.3 of the Listing Policy. The State Water Board recommendation is based on the following: Lahontan Regional Board staff had decided not to list this water body because staff thought it had insufficient information to make a decision to list. However, State Board staff finds there are 5 samples to make a decision and this meets the sample size requirements of Table 3.1 of the Listing Policy. On August 4, 2010 the State Water Board approved the staff recommendation to place this water body-pollutant combination on the 303(d) list. The final language for the recommendation is: Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. None of 12 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. Three out of five annual average datapoints exceeded the site-specific objective and this exceeds the allowable frequency listed in Table 3.1. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains the same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 28377, Nitrate | Region 6
Sheep Creek
LOE ID: | 7971
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 3
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Sheep Creek under the Region 6 SWAMP program between 2001 and 2005. Twelve samples each were analyzed for nitrite and nitrite plus nitrate, both expressed "as nitrogen." Nitrate was calculated by subtraction. Calculated "nitrate as nitrogen" concentrations included four estimated or below detection level values. The remaining 8 samples ranged from 0.046 to 0.24 mg/L. Expressed "as nitrate", these samples ranged from 0.207 to 1.08 mg/L. Two of five calculated annual averages were estimates due to estimated and below detection level data. The remaining averages ranged from 0.458 to 0.893 mg/L nitrate "as nitrate." The site-specific objective was violated in 3 of 5 years.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective from Lahontan Basin Plan Table 3-21 includes an annual average nitrate concentration of 0.3 mg/L and a 90th percentile value of 1.3 mg/L, both expressed "as nitrate."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples each (2 to 4 per year) were collected for nitrite and nitrite plus nitrate between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 28377, Nitrate | Region 6
Sheep Creek
LOE ID: | 7983
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Sheep Creek under the Region 6 SWAMP program between 2001 and 2005. Twelve samples each were analyzed for nitrite and nitrite plus nitrate, both expressed "as nitrogen." Nitrate was calculated by subtraction. Calculated "nitrate as nitrogen" concentrations included four estimated or below detection level values. The remaining 8 samples ranged from 0.046 to 0.24 mg/L. Expressed "as nitrate", these samples ranged from 0.207 to 1.08 mg/L. The MCL was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrate is 45 mg/L expressed "as nitrate," equivalent 10 mg/L expressed "as nitrogen."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples each (2 to 4 per year) were collected for nitrite and nitrite plus nitrate between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 30302 | Region 6
Sheep Creek

Pollutant: | Total Dissolved Solids
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Sources: | Source Unknown
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged and is as follows: Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). Five out of five annual average datapoints, based on only 2 to 4 samples per year, exceed the site-specific water quality objective. However, listing is not recommended because the data are not temporally representative. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the full range of seasonal and annual variability in streamflows and constituent concentrations expected in streams of the Lahontan Region. 3. None of 12 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. Five out of 5 annual average datapoints exceeded the site-specific objective and this exceeds the allowable frequency listed in Table 3.2. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. State Board Review and Conclusion: The April 19, 2010 State Water Board staff report for the 2010 Integrated Report recommended to place this water body on the 303(d) list for total dissolved solids based on the State Water Board staff determination that the data were collected over a broad period of time to meet section 6.1.5.3 of the Listing Policy. The State Water Board recommendation is based on the following: Lahontan Regional Board staff had decided not to list this water body because staff thought it had insufficient information to make a decision to list. However, State Board staff finds there are 5 samples to make a decision and this meets the sample size requirements of Table 3.2 of the Listing Policy. On August 4, 2010 the State Water Board approved the staff recommendation to place this water body-pollutant combination on the 303(d) list. The final language for the recommendation is: Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. None of 12 samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. Five out of 5 annual average datapoints exceeded the site-specific objective and this exceeds the allowable frequency listed in Table 3.2. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains the same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 30302, Total Dissolved Solids | Region 6
Sheep Creek
LOE ID: | 5303
Pollutant: | Total Dissolved Solids
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 5
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Total Dissolved Solids (TDS) under the Region 6 SWAMP program between 2001 and 2005. Concentrations of TDS in 12 quarterly samples ranged from 101 to 196 mg/L. The annual average objective was violated in 5 of 5 years.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective from Lahontan Basin Plan Table 3-21 includes an annual average of 56 mg/L and a 90th percentile value of 72 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 30302, Total Dissolved Solids | Region 6
Sheep Creek
LOE ID: | 5304
Pollutant: | Total Dissolved Solids
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Total Dissolved Solids (TDS) under the Region 6 SWAMP program between 2001 and 2005. TDS concentrations in 12 quarterly samples ranged from 101 to 196 mg/L. The MCL was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for Total Dissolved Solids is 500 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled: "Sheep Creek below Lake Arrowhead Scout Camp near Lake Arrowhead."
Temporal Representation: | Twelve quarterly samples (2 to 4 per year) were collected between 2001 and 2005.
Environmental Conditions: | Sheep Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Sheep Creek is designated for both the Cold Freshwater Habitat and the Warm Freshwater Habitat beneficial uses.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):